Conservation biologists at the University of Exeter have come up with a simple and effective means of reducing sea turtle entanglements and mortality from fishing nets: lights.

Green sea turtle. Photo credit: NOAA.

Working in Sechura Bay in northern Peru, a team of researchers including the biologists from U. Exeter and NOAA found that attaching green LED lights to the fishing nets drastically reduces the number of sea turtle deaths by 64 percent. Additionally, the lights did not interfere with the fish catch yields.

Using 114 pairs of gillnets, the researchers attached LEDs every ten meters on one net in each pair. The other net in the pair was left lightless as the control. These nets caught 125 sea turtles, while the illuminated nets caught 62. This is the first time light technology has been used in a working fishery to prevent bycatch. Coming in at $2 for each LED, the cost of saving one turtle totaled $34, and this cost could be reduced if this technique is implemented at a larger scale.

“This is very exciting because it is an example of something that can work in a small-scale fishery which for a number of reasons can be very difficult to work with,” said one of the lead authors, Dr. Jeffrey Mangel, in a news release. “These lights are also one of very few options available for reducing turtle bycatch in nets.”

Multiple species of sea turtle, including olive ridley, hawksbill, loggerhead and leatherback, can be found in Peru’s coastal waters. Unfortunately, thousands of these turtles die as bycatch in the gillnet fishery, which is the largest of Peru’s small-scale fisheries. It is estimated that this fishery sets 100,000 km (over 62,000 miles) of net every year.

“The turtle populations in the eastern Pacific are among the world’s most vulnerable,” said Dr. Mangel. “We are hoping that reducing bycatch, particularly in gillnets, will help with the management and eventual recovery of these populations.”

“Bycatch is a complex, global issue that threatens the sustainability and resilience of our fishing communities, economies and ocean ecosystems,” said NOAA’s assistant NOAA administrator for fisheries, Eileen Sobeck. “Funding research like this is key to NOAA’s efforts to reduce bycatch. Through this work, we can better protect our natural resources.”

Hoping to continue this effort to reduce bycatch of more critically endangered species in Peru, the researchers are working with larger fisheries and experimenting with different colored LED lights.